The fault of the wrongdoer is one of the preconditions for general tort liability. Nowadays, fault-based liability and strict liability are two equally important forms of liability that are not polar opposites but, rather, complement one another. This article focuses on the meaning of the fault of a tortfeasor. It considers the notion of fault in two European model rules (the Draft Common Frame of Reference and the Principles of European Tort Law), in the Estonian Law of Obligations Act, and also makes reference to German, French, English, and Russian tort law. We shall begin with a comparative discussion of the questions of general liability based on fault, fault capacity, various forms of fault, the burden of proving fault, and the importance of differentiating those forms of fault. Thereafter, we will treat the issues of fault in the context of liability for torts committed by another person and, also, borderline issues between fault-based liability and strict liability. This analysis seeks to offer the reader a basis for determining whether the regulations of Estonian tort law are justified or whether amendments should be considered within such a comparative-law framework.